Electrical connecter



June 18, 1935; Q E. F. SCHMIDT 2,005,475

ELECTRICAL CONNECTER Filed June l, 1932 Inventor fw uvclfsckmicw A ltorney Patented June 18, 1935 UNITED STATES PATENT FFlE 1 Claim.

My present invention relates to an improved electrical connecter adapted for use at the end of the cord or wires of electrical appliances, and designed to make the electrical connection with 4the well known type of electrical plug that is threaded into a wall socket, or outlet. Thus in carrying out my invention the connecter is permanently attached at the end of the cord or wires employed on an electric iron, a lamp, toaster, or other household appliance of this type, and in making the connection for illuminating the lamp (for instance) my improved connecter is plugged in to the usual plug that haspreviously been secured in the wall socket.

By the utilization of the connecter of my invention, the usual friction-held mechanical and electrical connection may be made with facility betweenthe prongs or blades of the connecter and the complementary socket-walls of the plug, or a positive, mechanical, lock, in addition to the friction-held connection, may be accomplished between the connecter and the socket-plug. Means are provided whereby strains imparted through a pull on the cord or wires, (as when grasping the wire and jerking the connecter from the plug, by hand) are prevented from reaching the terminals of the connecter, thereby preserving the terminal connections and avoiding loosening ofithe wires.

The improvements involved in the new connecter also involve a novel, resilient and flexible handle for the connecter to be grasped by hand when making or unmaking the connection to the wall-plug. The invention consists in these, and

"other novel combinations and arrangements of parts as will hereinafter be more fully set forth and claimed.

In the accompanying drawing I have illustrated one complete example of the physical embodiment of my invention wherein the parts are combined and arranged according to the best mode I have thus far devised for the practical application of the principles of my invention.

Figure 1 is a side View of my connecter applied to and positively locked on the usual threaded plug for a wall socket or outlet.

Figure 2 is a longitudinal sectional detail View of the device of Figure 1.

Figure 3 is a face view of the connecter.

Figure 4 is a perspective view of the grip or clamp device mounted within the connecter for gripping the wires or cord.

The connecter of my invention is designed for use with the well known type of plug l, having the screw-threads 2 for screwing into a complementary socket, or pocket in an outlet box, and this plug has the usual spaced sockets 3 that accommodate the prongs or blades found on most connecters now in use. In converting the screw plug I to my own use I equip the plug with a pair 5 of laterally extending, diametrically arranged, pins 4, l, having heads 5, 5. These pins may be screws, as indicated in Figure 2, that are threaded into the plug, or the pins may be embedded in the plug when the latter is cast.

The connecter plug 8 of my invention is cylindrical in shape, of insulating material, and provided with an axial bore or hole I, and the round enlargement or head 8 is fashioned with an annular flange F on its face to provide a depression therein. The annular, rear face 9 of the head forms an annular shoulder for use in retaining a loosely mounted cup-shaped sleeve H] on the connecter. This sleeve has a hole H fitting neatly about the exterior of the connecter, and the diameter of the sleeve is such as to fit the sleeve neatly over the exterior faces of the head of the connecter and the outer end of the threaded plug l.

The free edge of the cylindrical sleeve is provided with a pair of diametrically arranged bayonet slots l2, it that are adapted to co-act with the pins #5, 4, of the screw plug in looking the sleeve and connecter to the screw plug. A spring i3 is coiled about the exterior of the connecter, within the sleeve and between the shoulder 9 of the connecter and the end of the sleeve, and the tendency of this spring is to push the sleeve away from the front face of the connecter, or away from the screw plug when the connecter, is attached to the screw plug. -Thus, the sleeve is provided 3r with a knurled ring it by means of which the sleeve may be pushed toward the screw plug, against the tension of the spring [3, to cause the slots l 2 to slip over the pins 4, and then by a twist or turn of the sleeve, the bayonet slots are engaged with the pins in such manner as to lock the sleeve and the connecter to the screw plug. For releasing the lock joint, the sleeve is turned in reverse direction, to free the bayonet slots from the pins, and then the spring is free to project the sleeve to the right in Figures 1 and 2. A stop ring I5 is fixed at the rear end of the connecter, on its periphery, to limit the movement of the sleeve under action of the spring.

A pair of spaced blades or prongs I6 and I! of usual type project from the face of the connecter, for insertion into the two complementary sockets or holes 3, 3, of the screw plug, and it will be understood that these prongs or blades adapt the connecter of my invention for use with the usual screw plugs, as Well as for use with the converted screw plug 6 illustrated herein.

The blades or prongs are integral with arcuate terminal arms or plates it, that are secured by screws 119, against the flat face of the head 8, within the depression of the face of the head of the connecter, and the ends of the wires 25 are provided with terminal loops 23, through which the screws pass. The face or" the connecter is countersunk at 22, and grooved as at 25 to accommodate the wires and the terminals or loops, and the latter are firmly secured by the screws. The wires are passed through the hole or bore l of the connecter, and they also pass through a flexible and resilient handle or knob 2% that is secured at the rear end of the connecter.

This handle or knob is fashioned, preferably, of rubber and is soft and elastic for convenience in handling, and may be grasped between the fingers and thumb when the connecter is to be attached to or detached from the screw plug. The handle is fashioned with an exterior, annular flange and the rear end of the connecter is provided with an inwardly projecting flange 25 that forms a grooved seat 2i to receive the flange of the handle, and retain the handle by the flange In the seat 2? a washer or circular disk 28 is mounted transversely of the bore of the connecter and of the handle 24, and this disk, which is countersunk on one side at 29 is provided with a central opening 39 having tapering walls. As best seen in Figure 2, the maximum diameter of this tapered opening is approximately the same as the bore of the connecter, while the minimum diameter is considerably less than the bore '5. Thus, the flexible tapering walls 38 will permit the wire or cord to be passed, from right to lei t in Figure 2 through the bore of the connecter,

in order that the wires may be connected to the terminal screws, and as the wire is thus passed, the tapering walls are slightly spread or forced open. Under there conditions, the tapering walls form a jaw that grips the cord, the elasticity or resiliency of the material of the jaw holding the cord out of contact with the hard surface of the bore of the connecter, and avoiding abrading of the insulation on the cord. This gripping jaw also serves to take the strains of a pull on the cord, away from the terminal connections of the wire. As is the custom with many people, in detaching the connecter from the screw plug, the detachment is made by grasping the cord or wire and giving the latter a jerk. This effectually detaches the connecter, but it is also likely to disconnect the terminals of the wires. When the connecter is equipped with the grip of my invention, and a jerk is given to the wire or cord, this action causes the tapering walls or jaw to grip the cord with a cam action, and the grip of the disk on the cord causes the strain of the jerk to be imparted to the connecter, through the disk, instead of being imparted or translated through the wire to the wire-terminals.

As herein described and illustrated it will be apparent that I have provided an electrical connecter that is comparatively inexpensive in cost of manufacture, which is simple in construction, and durable, and well adapted to withstand careless manipulation in use. The device is suitable for employment in shops, factories, offices, homes, and other places, for making positive and secure connections with various electrical appliances, which may be locked in position, when desired, to avoid the annoyance caused by plugs being pulled out of their sockets. The locking device, when used, is especially adapted where the screw plug and the connecter are employed as an overhead suspension connection, and the cords or wires suspend the electrical appliance, as a lamp. Under these conditions, the weight of the load is taken off the frictionally engaged prongs or blades, and is borne by the bayonet slot and pin connection, and the grip 3l also takes the weight of suspension off the terminals of the wires, thus avoiding strain at the terminals.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

The combination with an electrical connecter having an enlarged head forming an annular shoulder, said head having a recessed face and means therein for making electrical contact. with a plug, and a spaced stop ring on the exterior of the reduced body of the connecter, of a cylindrical cup shaped locking sleeve mounted on the head projecting over the body of the connecter having an annular inturned flange and longitudinally slidable on the body of the connecter,"

said flange adapted to co-act with said stop ring, and a spring enclosed by the sleeve coiled about the body of the connecter and interposed between and abutting against said shoulder and. 

